4_GB1_LearnRes_Web

The Learning Resource goal is to use the Internet and become independent of the textbook used by the STC biology department -- taking advantage of learning tools on the Internet such as YouTube videos, and external links (e.g., Wikipedia). It is a project in progress (hence the running dog)... In addition the STC transfer of Blackboard to a new Blackboard Learn 9.1 platform is ongoing. However, understand that these learning resources are only an overview. Don't forget that your complete and most important learning resource is your textbook. You are expected to read it...

Ch. 14, 15, 16

Ch. 17, 18, 19, 20, 32 --and-- in part 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31

Ch. 20, 21, 22, 234, 24, 25

This page is going through major updates.

If you see errors, misspellings, incorrect links, please let the instructor know in the HELP DESK.

Back...

What is the evidence for evolution? Stated Clearly.

Evolution

From S. S. Mader. 2010. Biology. McGraw-Hill.

- - - Evolution - - -

Charles Darwin (1809 -- 1882) was an English naturalist who established that all species of life have descended over time from common ancestry. He proposed the scientific hypothesis (later elevated to a scientific theory) that this branching pattern of modification through descent (later called evolution) resulted from a process that he called natural selection.

Darwins five-year voyage on HMS Beagle, 1831 - 1836, -- from England, to Cap Verde Islands on the west coast of Africa, to the South America continent, to Galapagos Islands, to New Zealand, to Australia, several islands in the India Ocean, Cape of Good Hope on the tip of southern Africa, some islands in the south Atlantic, back to the east coast of South America, then back to Cap Verde Islands, then the Azores Islands, and then finally returned to England -- and publication of his journal of the voyage, made him famous -- both as popular author and an eminent scientist.

The map shows the route Darwin traveled on the HMS Beagle around the world from 1831 to 1836. (S. S. Mader. Biology. Ed. 10. McGrawHill Higher Education, Boston.)

Charles Darwin. (S. S. Mader. Biology. Ed. 10. McGrawHill Higher Education, Boston.)

--- If you wish to read about the whole trip, here is a good web site: AboutDarwin.com

!. The Galápagos Islands are off the western coast of:

A. Africa
B. Australia
C. Europe
D. North America
E. South America

2. The Galápagos islands are a part of what country?

A. England
B. Ecuador
C. El Salvador
D. Ethiopia
E. Equatorial Guinea

He published his hypothesis with convincing evidence in his 1859 book On the Origin of Species.

The scientific community and much of the educated general public -- except for many religious people -- came to accept evolution as a fact already in his lifetime 150 years ago.

It was not until the emergence of the modern evolutionary synthesis from the 1930s to the 1950s that a broad consensus formed that Natural Selection was the basic mechanism of evolution.

Today the modified form of Darwin's scientific discovery is the unifying theory of the biology, explaining the diversity of life.

(Paraphrased from Wikipedia, http://en.wikipedia.org/wiki/Charles_Darwin.)

3. Person that perhaps was the first expressing ideas about evolution?

A. Anaximander
B. Wallace
C. Darwin
D. Mendel
E. Linné

When you reach this page, you have most likely already read the reading assignments for the so called Town Hall Meeting about Evolution, and will or have already participated in the discussions. In other words, you already know quite a bit about Evolution.

If you have not yet read the reading assignments, click on the link below, which will take you to the Town hall instructions.

--- History of Evolutionary Thought ---

Darwin's voyage on the ship HMS Beagle became an expedition that lead to dramatic changes in many fields of science. Beginning in December, 1831, the voyage lasted almost five years and Darwin spent most of that time on land investigating geology and making natural history collections, while the Beagle surveyed coasts. Darwin kept careful notes of his observations and speculations, and at intervals during the voyage his specimens were sent to Cambridge together with letters including a copy of journal for his family.

On their first stop ashore at St. Jago, Darwin found that a white band high in the volcanic rock cliffs included seashells. In Brazil Darwin was delighted by the tropical rainforest. In Patagonia he made a major find of fossil bones of huge extinct mammals in cliffs beside modern seashells, indicating recent extinction with no signs of change in climate or catastrophe. On rides into the interior to explore geology and collect more fossils, he found that two types of a bird called rhea had separate but overlapping territories and looked like the African ostrich.

Darwin experienced an earthquake in Chile and saw signs that the land had just been raised, including mussel-beds stranded above high tide, and high in the Andes he observed seashells. On Galapagos Islands Darwin found mockingbirds similar to those in Chile (on the mainland), but differing from island to island. He heard that slight variations in the shape of tortoise shells showed which island they came from. In Australia, the platypus seemed so unusual to Darwin that he thought it was almost as though two distinct Creators had been at work.

When organizing his notes as the ship sailed home, Darwin wrote that he had growing suspicions about the "stability of species" and that observations he had done seemed to "throw some light on the origin of species". When the Beagle returned to England in October 1836, Darwin was already a celebrity in scientific circles. (Modified from Wikipedia http://en.wikipedia.org/wiki/Charles_Darwin)

For more information on Darwin's trip. (The link will open in a new window.)

Prior to Darwin, most people had an entirely different way of viewing the world. They believed that then Earth was only a few thousand years old and that species had remained exactly the same since creation. Darwin was not the first person to attempted to explain evolution, but all earlier attempts lacked a mechanism. Count Buffon (George-Louis Leclerc) and Charles Darwin's grandfather, Erasmus Darwin, are two persons who speculated about evolution, and both influenced Darwin, but both lacked the mechanism by which evolutionary descent might occur.

Charles Darwin had studied the writings of his grandfather Erasmus Darwin, Count Buffon, and also many other scientists, such as James Hutton, Charles Lyell, Jean-Baptiste de Lamarck, Thomas Malthus, Carolus Linnaeus, and other original thinkers. He had his five-year voyage to think about the ideas of these authors, and from them collectively, he built a framework that helped support his theory of descent with modification, and in doing so he also applied the concept of human reproductive potential stressed by Thomas Malthus, (1766 - 1834), to all organisms and concluded that the Earth is much older than previously thought.

PROBLEM:
--- Lacking a mechanism
--- Not understanding how old the Earth is

Having a better understanding for the Age of the Earth helped Darwin to came up with a mechanism: Natural Selection.

More about Natural Selection later...

For more information on Pre-Darwinian Theories. (The link will open in a new window.)

(Scientific American) Another Inconvenient Truth: The World's Growing Population Poses a Malthusian Dilemma

The Age of Our World Made Easy (estimating the age of the Earth with isotopes)

--- Darwin's Theory of Evolution ---

One body of evidence Darwin turned to for his theory was Artificial Selection. Artificial selection is changes done by humans in crops, livestock and pets. Artificial selection shows the power of an outside selective force acting on a species -- humans have bred dogs, cats, birds, farm animals, crop plants for hundreds, sometimws for thousands, of years. Darwin reasoned that if farmers and breeders could bring about such big changes in the short time span of human recorded history, what could nature do over millions of years?

"Darwin developed his theory in part because of his study of how dogs and pigeons were bred. He knew several breeders of dogs and asked them how they selected certain traits. According to the American Kennel Club, there are over 150 different dog breeds, from tiny Chihuahuas to giant Great Danes, but they are the same species (Canis familiaris) and all are descendants of wolves." http://www.windows2universe.org/cool_stuff/tour_evolution_7.html

Raised pigeons -- all breeds are descended from the rock dove -- was a popular hobby at the time when Darwin was formulating his theory (and still is today). Breeders competed to produce varieties with a particular color or beak shape, and Darwin did the same, and at one point his flock grew to 90 birds, but Darwin was interested in evolution, not pigeon shows.

Click on the link to navigate to the Darwin Exhibit at the American MNuseum of Natural History.

Darwin,together with another naturalist Alfred Wallace, (1823 - 1916), suggested natural selection as a mechanism for evolutionary change. In dog breeding, artificial selection by humans, the dogs with the desirable characteristics are allowed to reproduce. In nature, natural selection, the most well-adapted animals in the wild are more likely to survive and reproduce. Today most biologists agree that evolution occurs as a result of Natural Selection.

Fathers of Evolution: Charles Darwin and Alfred Russel Wallace.

Natural Selection

NATURAL SELECTION

def. Natural Selection: 1. A microevolutionary mechanism that encourages the passage of beneficial genes to future generations, and discourages harmful or less valuable genes.

Evolution using Natural Selection as the mechanism works as follows -- Natural Selection Steps:

Living organisms have more offspring than can survive.

The offspring of living organisms have inheritable variations.

Living organisms compete for resources, and some inheritable variations give an advantage, and some give a disadvantage, in the struggle for survival.

Living organisms with the most useful variations will survive, have higher reproductive success, and pass on their useful traits to their offspring.

In this way living organisms will adapt to change in the environment or to new environments, and change. Given enough time, new species will evolve.

This means that all organisms have a "common descent" -- all living organisms are related in a "Tree of Life".

4. Which of the following is NOT a component of Darwin's principle of natural selection?

A. New alleles are constantly produced through mutation
B. Populations exhibit great variation
C. Organisms produce more offspring than can survive
D. Over time adaptive phenotypes increase in a population.
E. Over a long period of time, organisms will change and given enough time new species will evolve

5. A microevolutionary mechanism that encourages the passage of beneficial genes to future generations, and discourages harmful or less valuable genes.

A. evolution
B. natural selection
C. dispersal
D. population explosion
E. adaptive radiation

Tree of life and common ancestry

Source: http://tolweb.org/tree/ Used for educational purposes.

Source: ... Used for educational purposes.

Source: ... Used for educational purposes.

Click on the"Understanding Evolution logo above for a simple and easy to understand explanation of natural selection...

Need to review genetics?

--- Links to Genetics ---

Evolution shows up as a Change in Allele Frequencies

-- Some of the alternative forms of a trait (alleles) becomes more (or less) common.

6. Change in allele frequency in a population of organisms (evolutionary change within a lineage)

a. Chemical evolution
b. Biological evolution
c. Cultural evolution
d. a and b
e. a, b, and c

What can 'evolve'?

7. Which of the following evolve?

A. populations
B. individuals
C. animals only
D. plants only
E. animals and plants, but not humans

def. Population: A group of individuals of the same species occupying a given area.

def. Gene Pool (Allele Pool): The various genotypes (alleles) in a population (pool of genetic variations)

Individuals in a Population Vary (Deviations in the Allele Pool)

1. Genetic information are in the genes -- specific regions on DNA.

2. In diploid organisms there are at least two forms -- these forms are called alleles

3. Individuals inherit different combinations of alleles. -- this gives variation to a population

Populations Evolve (Individuals do NOT evolve)

1. Individuals DO NOT CHANGE, BUT pass on their genes (alleles) to future generations of the population

2. If the frequency of certain alleles of a trait change in the population, then

3. Future generations change, they EVOLVE

How does Biological Evolution occur?

How and if evolution occurs is based upon:

A. genetic traits (the frequencies of alleles)
B. evolutionary mechanisms (microevolutionary processes -- natural selection the most noted)
C. survival characteristics

A. Genetic Traits

def. Allele Frequency: The relative abundance of each kind of allele, carried by the individuals, in a population.
def. Allele: One of two, or more, slightly different molecular forms of a gene that code for different versions of the same trait.

• Evolution shows up as a Change in Allele Frequencies

>> some form of a trait, an allele becomes more or less common

>> genetic traits will change from one generation to the next

Thought Experiment

The Hardy-Weinberg Law states that allele frequencies will not change, and evolution will not occur, if ALL of the following five conditions are met:

1. No mutations (no new alleles; e.g., no bacterial resistance against antibiotics).

2. No gene flow in and out of a population (no movement of alleles).

3. No genetic drift (no movement of alleles).

4. No selection (no selective agent favor a particular allel over another; ; e.g., no insect resistance against pesticides is favored).

5. All mating is random (individuals pair by chance and not by allele selection; "no attaction" just select your spouse at random).

In real life these five conditions are rarely, if ever, met, and allele frequencies in the gene pool of a population DO change. evolution will occur -- or at least the potential for evolution is there.

Question :

Does evolution occur?

Do allele frequencies change?

If you have a baby will it be a copy of you?

Answer:

A baby is different looking than the parents.

so

A baby has different alleles than the parents.

so

Conclusion :

1. YES, the allele frequency do changed (compared to the parents).

so

2. Yes, the potential for evolution is there (i.e., A potential for CHANGE -- if reproduction occur -- in the POPULATION)

__________

B. Mechanisms

The mechanisms of evolution are microevolutionary processes.
def. Microevolution: small scale changes in allele frequencies.

1. Natural Selection -- best trait survives/mate
2. Other mechanisms
a. Mutations -- DNA changes and gives rise to new traits
b. Nonrandom mating -- only organisms with certain traits mate
c. Random drift -- certain traits promoted by accident
d. No gene flow -- organisms isolated preventing gene mix

The mechanisms of evolution influences the transmission of alleles from one generation to the next. (influences the “direction of evolution”)

C. Survival Characteristics

-- Certain traits (alleles) are better for survival

def. Natural Selection: 1. A microevolutionary mechanism that encourages the passage of beneficial genes to future generations, and discourages harmful or less valuable genes.

In order to survive an organism must:

1. Be able to adopt to changes

>> because the environment is always changing

2. The adaptations must be genetically controlled

>> so the survival characteristics can be passed on to the next generation,

(adaptations not under genetic control cannot be passed on.)

Real example of survival characteristics at work...

A much used example of how natural selection results in adaptation to the environment is industrial melanism. The most famous example is industrial melanism in Biston betularia, the Peppered Moth.

The evolution of the peppered moth over the last two hundred years. Originally, the vast majority of peppered moths had light color, which effectively camouflaged them when sitting on the light-colored trees and lichens. Because of widespread pollution during the Industrial Revolution in England, many of the lichens died out, and the trees that peppered moths rested on became blackened by soot. This caused most of the light-coloured moths to die off from predation. At the same time, the dark-coloured moths became the most common variety because of their ability to hide on the darkened trees.(Paraphrased from, http://en.wikipedia.org/wiki/Peppered_moth_evolution)

Today, with improved environmental standards, the light-colored peppered moths have again become common, and the term "industrial melanism" has been coined to refer to the genetic darkening of species in response to pollutants. Because of this and easy-to-understand example of adaptation to the environment, the peppered moth has become a common example used in explaining or demonstrating natural selection." (Paraphrased from http://en.wikipedia.org/wiki/Peppered_moth_evolution)

(Source Wikipedia: http://en.wikipedia.org/wiki/Peppered_moth_evolution)

VIRTUAL EXERCISE *.

Read the text in this box and view the YouTube video, "What is Natural Selection" by Stated Clearly. Then click on the link below and do the Natural Selection exercise on the page you land on (looks like the figure above). (If you are in a F-2-F class and doing this in the biology computer lab, the instructor will show the video, since the computers in the lab have no speakers...)

What is Natural Selection? Stated Clearly
Source URL: https://www.youtube.com/watch?v=0SCjhI86grU

Natural Selection Activity. Read the page you land on and follow the instructions. You must keep eating beetles until you reach level 5 -- or until the instructor informs that the activity has ended. If you reach level 5 before the instructor ends the game, you may sign the attendance roster and get ready for Thanksgiving...

Here is the link:
http://www.nhm.ac.uk/nature-online/evolution/what-is-evolution/natural-selection-game/the-evolution-experience.html

Have a nice Thanksgiving...!

--- Evidence of Evolution ---

There are many different areas of evidence supporting the scientific theory of evolution. In this class this part will be covered in detail in the part of the class called the Town Hall Meeting. Four areas will be investigated and discussed:
1. Fossil Evidence
2. Biogeographical Evidence
3. Anatomical Evidence
4. Biochemical Evidence

(Textbook page indicator for evidence of evolution: Pages 236 - 237, and 242 - 246, Essentials of Biology, Mader and Windelspecht, Ed. 3.
Pages 269 - 270, and 276 - 279, Biology, Mader, Ed. 10.
If you are using different textbook editions the page numbers may vary.)
More about the evidence next semester in General Biology II...

- Introduction to Evolution and Natural Selection (Khan Academy You Tube) -
COMMENT ON THE YOUTUBE: Good job, Sal! Most of the videos explaining evolution you find on youtube are very complex, fast paced, confusing and use a very? complex, scientific language. This is a very calm and thorough explanation, and I'm sure many will understand and enjoy it!

If you have problems understanding the concept of the "natural selection" here is an excellent YouTube video from Khan Academy, which will help you understand -- even though some of the information is beyond what is required for this class. Sometimes YouTube videos disappear. Hopefully it will not happen often, but if it does there is nothing that can be done about it...

Introduction to Evolution and Natural Selection

--- Conclusion (& including humans in it...) ---

Evolution happens (populations change over time).

Evolution happens gradually (populations change over hundreds to thousands of years usually -- but there are exceptions).

Speciation happens -- one species splits into two species (long time tree of life branching process).

All species on Earth share common ancestry (as a result of splitting lineages from one ancestral life form).

Source: http://web.uconn.edu/gogarten/ -- Used for educational purposes.

Tree of life and common ancestry

Tree of life with and without extinct lineages. Most depictions of the trees of life that are derived from molecular data only consider extant organisms (i.e. lineages that have representatives alive today).

8. The organisms with the longest evolutionary history are

a. prokaryotes
b. eukaryotes
c. photosynthesizers
d. mosses
e. worms

Source: Comparative genomics of higher primates. ... http://www.mpg.de/19230/Comparative_genomics -- Used for educational purposes.
-----------------------------------------------
"The common chimpanzee and the bonobo or pygmy chimpanzee are our closest living relatives, with whom we share a common ancestor that lived 5 - 7 million years ago. Humans and chimpanzees share a common ancestor with gorillas -- the other major species of African apes -- that lived 6 - 8 million years ago, whereas the common ancestor shared with the Asian orangutans lived 12 - 16 million years ago."

"Many species that were more closely-related to humans have lived and become extinct since the time of the chimpanzee-human ancestor. They are collectively called hominins. One hominin is the Neandertal, whose lineage diverged from ours 300,000 - 500,000 years ago. Neandertals lived in western Eurasia, sometimes alongside our ancestors, until they became extinct around 30,000 years ago."
-----------------------------------------------

Source: http://www.wildchimps.org/wcf/english/files/wissen.htm -- Used for educational purposes.
-----------------------------------------------
"Only 1.6% of our genetic material, the so called DNA, differs between us and our chimpanzee cousins. Five million years ago, the last common ancestor of humans and chimpanzees lived and died somewhere in Africa, and so we share the same inheritance with the chimpanzees."
-----------------------------------------------

9. Taxonomic category including humans, apes, monkeys, and lemurs, and their recent ancestors.

A. Primates
B. Anthropoid
C. Hominidae
D. Hominoid
E. Mammalia

10. Which one of these is NOT a primate?

A. lemurs
B. monkeys
C. gorillas
D. humans
E. Proconsul
F. All of these are primates

(Source: Click on the video.)

"Scientists using chemical isotopes in ancient soil to measure prehistoric tree covering effect, shade have found that grassy, tree-dotted savannas prevailed at most East African sites where human ancestors and their ape relatives evolved during the past six million years." (Source: http://www.informafrica.com/blog/human-evolution-six-million-years-of-african-savanna/)

11. Cradle of human-kind?

a. North America
b. South America
c. Europe
d. Africa
e. Asia

We will leave Africa for next semester...

VIRTUAL EXERCISE **.

"Scientists think that we shared a common ancestor with chimpanzees around 5 to 8 million years ago. since then, the human skull has gradually changed shape. "Compare the skulls of chimpanzees, modern humans, and some extinct species of hominid, such as Australopithecus afarensis, to see which were most closely related and how skull shape has evolved." (Natural History Museum, London. http://www.nhm.ac.uk/nature-online/life/human-origins/modern-human-evolution/3d-hominid-skulls/)

Read the text in this box and view the video. Then click on the link below and study the skulls on the page you land on (looks like the figure above). (If you are in a F-2-F class and doing this in the biology computer lab, the instructor will show the video, since the computers in the lab have no speakers...)

How Bones Support Human Evolution TaylorX04

Here is the link:

http://www.nhm.ac.uk/nature-online/life/human-origins/modern-human-evolution/3d-hominid-skulls/

- - - Connecting the Concepts - - -

"Before the 1800s, most people believed (and clearly today also some people uneducated in science) that each species had been created at the beginning of the world, and that modern organisms were essentially unchanged descendants of their ancestors."

"At the time Charles Darwin boarded the HMS Beagle, he had studied the writings of his grandfather Erasmus Darwin, James Hutton, Charles Lyell, Jean-Baptiste de Lamarck, Thomas Malthus, Carolus Linnaeus, and other original thinkers. He had ample time during his five-year voyage to reflect on the ideas of these authors, and from them collectively, he built a framework that helped support his theory of descent with modification."

"By the time he reached the Galapagos Islands, Darwin had already begun to hypothesize that species could be modified according to the environment. In other words, like other scientists, Darwin used a testable hypothesis to explain his observations. His observations supported the hypothesis. He concluded that finches on each island varied from one another and from mainland finches because each species had become adapted to a different habitat; therefore, one species had given rise to many."

"The fact that Alfred Russel Wallace simultaneously proposed natural selection as an evolutionary mechanism suggests that the scientific community was ready for a new conceptual understanding of life's diversity on Earth."

"The theory of evolution has quite rightly been called the grand unifying theory of biology. Fossils, comparative anatomy and development, biogeography, and biochemical data all indicate that living things share common ancestors."

"As the Earth's habitats change over millions of years, those individuals with the traits best adapted to new environments survive and reproduce; thus, populations change over time." -- i.e., EVOLVE ...

(Source: Mader, S.S. 2010. Biology. Ed. 10. Used for educational purpose.)